This invention generally relates to an air return bulkhead used in combination with a transport temperature control system to provide the requisite airflow through the conditioned space; and more particularly the invention relates to a transport temperature control system air return bulkhead that includes a first bulkhead section and a second bulkhead section, where each of the bulkhead sections is movable relative to the other bulkhead section.
Temperature control systems for use in trailers are mounted on a trailer which defines a conditioned space, and the air in the conditioned space is maintained at a predetermined desired temperature by the temperature control system which is typically mounted on the front trailer wall or panel. The temperature control system evaporator extends through the front trailer wall and into the conditioned space.
Palletized cargo is loaded into the conditioned space and the evaporator serves to cool and force the conditioned air into the conditioned space and around the palletized load in the manner generally indicated by arrows 150 in FIG. 1. The conditioned air is forced rearwardly out the evaporator, around the back of the load, below the load and back to the front of the trailer.
An air return bulkhead is located at the front of the trailer and is typically attached by rivets or the like to the interior of the front trailer wall behind the temperature control unit. The upper portion of the bulkhead is fitted around the evaporator unit. A seal is formed between the bulkhead and the evaporator and conditioned space wall so that the conditioned space air that is drawn behind the bulkhead is flowed into the evaporator and also air in the conditioned space does not short cycle from the conditioned space to a location behind the bulkhead. In order to achieve the requisite seal between the bulkhead and evaporator unit, during bulkhead installation it is typically necessary to cut away or otherwise remove a portion of the bulkhead in order to fit the bulkhead around the evaporator and form the requisite seal therebetween.
When it is necessary to service the temperature control unit evaporator, the prior art bulkhead must be completely removed or disassembled from its fixed position on the trailer wall. Removal of the bulkhead can be quite time consuming. Additionally, the regular removal and reattchment of the bulkhead to the trailer wall can reduce the integrity of the seals between the bulkhead and evaporator and can weaken the bulkhead or result in cracks developing in the bulkhead. Conditioned space air short cycles through the cracks or gaps in the seals behind the bulkhead. Permitting the short cycling of conditioned space air reduces the effectiveness of the temperature control system.
Prior art bulkheads are large. Therefore, in order to ship the bulkheads to customers, prior art bulkheads are typically manufactured as a single piece and then cut into two or more discrete sections for shipping. When installed, the bulkhead sections are overlayed and fixedly connected by screws or other conventional fasteners. The seam or seams where the bulkhead sections are connected are additional locations where conditioned space air may short cycle back behind the bulkhead.
The foregoing illustrates limitations known to exist in present air return bulkheads. Thus, it is apparent that it would be advantageous to provide an alternative bulkhead design that overcame the limitations set forth above by eliminating the need to remove the bulkhead from the trailer wall in order to service the evaporator and also by eliminating the need to cut the bulkhead into discrete sections in order to ship the bulkhead. Accordingly, a suitable alternative that overcomes the limitations associated with prior art bulkheads is provided including features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing an air return bulkhead comprising a first bulkhead portion and a second bulkhead portion joined by a convoluted hinge member. The hinge permits the portions to be moved relative to each other and may be collapsed for easy shipment, and as a result does not need to be reattached when it is installed in the trailer. Additionally, when servicing the temperature control system is required, only the connection members securing the second bulkhead portion need be removed. Once the fasteners are removed, the second bulkhead portion can be moved away from the trailer wall making it easy for a service technician to service the system.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.